CCR5 & CXCR4 Antagonist & Agonist Binding Site Structure

耐药性问题，潜在的病毒库，以及当前抗艾滋病毒药物的毒性效应要求 开发具有不同作用模式的新型抗逆转录病毒药物。一种很有希望的药物开发方法 发育是对艾滋病毒进入细胞的干扰。进入艾滋病毒是一个复杂的过程，需要 HIV包膜蛋白gp120与细胞共受体(CCR5或CXCR4)的结合。这项提议旨在 为了加深对CCR5和CXCR4结构的了解，包括 有助于参与激动剂激活的拮抗剂结合和接触残基的替代模式。 需要CCR5才能进入的病毒分离株是从一种 一个人对另一个人。需要CXCR4进入的病毒株通常在感染的后期出现，包括 被认为是更具致病性的，与CD4T淋巴细胞的严重丧失和 由于严重的免疫缺陷而发生机会性感染。几个小分子 阻断病毒感染的CCR5或CXCR4的拮抗剂已被确定为有希望的药物先导 制药公司，但他们在受体上的结合部位和阻断艾滋病毒的机制是 人们对此知之甚少。该项目将使用拮抗剂和激动剂分子的高亲和力光活性类似物。 研究CCR5和CXCR4中的相互作用部位，并将调查残基在 通过定点突变产生的交联点。我们还将调查在构象上的变化 通过研究单抗的相互作用部位，导致HIV结合的激活或拮抗的CCR5 针对CCR5拮抗剂或激动剂结合构象的抗体。拟议的研究将 更好地了解CCR5和CXCR4的结构和功能，并旨在提供 有助于设计更有效的药物，以抑制艾滋病毒进入，同时将副作用降至最低 激活或阻断CCR5和CXCR4的正常功能。

Problems of drug resistance, latent viral reservoirs, and the toxic effects of current anti-HIV drugs call for the development of new anti-retrovirals with different modes of action. A promising approach for drug development is interference with the entry of HIV into cells. HIV entry is a complex process that requires binding of the HIV envelope protein gp120 to a cellular co-receptor (CCR5 or CXCR4). This proposal seeks to enhance understanding of the structure of CCR5 and CXCR4, including the amino acid residues that contribute to alternative modes of antagonist binding and contact residues involved in agonist activation. Virus isolates that require CCR5 for entry are the predominant infectious forms of HIV transmitted from one person to another. Virus strains that require CXCR4 for entry often emerge in the late stages of infection, are considered to be more pathogentic, and correlate with severe loss of CD4+ T lymphocytes and the development of opportunistic infections due to severe immunodeficiency. Several small-molecule antagonists for CCR5 or CXCR4 that block virus infection have been identified as promising drug leads by pharmaceutical companies, but their binding sites on the receptors and the mechanism of HIV blocking are poorly understood. This project will use high-affinity photoactive analogs of antagonist and agonist molecules to examine the interaction sites in CCR5 and CXCR4andwill investigate the roles of the residues at the crosslinking sites by site-specific mutagenesis. We will also investigate the changes in the conformation of CCR5 that result in activation or antagonism of HIV binding, by studying the interaction sites of monoclonal antibodies specific for the antagonist- or agonist-bound conformations of CCR5. The proposed studies will lead to a better understanding of the structure and function of CCR5 and CXCR4 and aim to provide information useful for the design of more potent drugs that inhibit HIV entry while minimizing side effects due to activating or blocking normal functions of CCR5 and CXCR4.